It is well known that grounds are generally covered by synthetic material or by wood inlaid flooring to provide a surface which is more aesthetic and more comfortable.
For sports purposes or other indoor recreational, the flooring has to have suitable properties, as for example rebounding, shock-absorbing, and/or stability properties.
Usually, a wood flooring system comprises a substructure and an upper flooring arranged above and supported by the substructure.
For example, EP1611930 discloses a gymnastics exercise floor comprising a rectangular subfloor provided with panels and a compressible top layer provided on the panels. The panels in the rectangular subfloor are diagonally arranged. The top layer is furthermore arranged in strips on the subfloor oriented parallel, with the strips of the springy top layer including an acute angle with the panels.
U.S. Pat. No. 5,299,401 discloses an athletic flooring system wherein the subfloor is made up of a first and a second wood subfloor wherein the first subfloor is less continuous and more elastic than the second subfloor and wherein the boards of the first and second subfloors cross each other at an angle of 50 degree. The subfloors act in cooperation with a pad and with void volumes distributed in the subfloor to give the flooring system elastic properties.
Among a large number of drawbacks, these known wood floorings substructures are constructed on site leading thus to an increasing labour cost and to an increasing of installation complexity.
US2002189184 discloses a ladder-shaped subassembly for use in assembling a subfloor for an athletic floor that is anchored. Long nailing strips form the long members of the ladder-shape while shorter transverse anchor strips secured below the long members form the rung members of the ladder shape and comprise resilient pads secured to their lower face. This solution presents the drawbacks of having poor dimensional stability.